Do Dishwashers Deplete Your Home’s Hot Water?

All dishwasher brands require very hot water for optimal performance. With 30 years of experience in appliance repair, I’ve encountered many dishwashers that struggle to clean properly or melt soap due to inadequate water heating.

The 120-degree water from your home’s heater typically isn’t hot enough for your dishwasher. That’s why most dishwashers raise the water temperature to 160 degrees, effectively sanitizing and dissolving dishwasher soap.

If you open your dishwasher door 30 minutes into the cycle, you should see a significant steam release. If not, there may be an issue with your dishwasher’s heating system.

The most common reason for poor heating is the water inlet valve not allowing enough water to activate the heater. At the 30-minute mark, you should see the water level high enough to touch the heating element at the bottom.

Some dishwashers, like Bosch and Miele, have concealed heating elements. On Bosch dishwashers, the water level should reach the top of the round plastic filter handle, while on Miele, it should reach the bottom of the white plastic filter handle.

When the fill valve doesn’t let in enough water, the water won’t heat sufficiently to clean dishes. Replacing the fill valve can resolve this issue.

Other potential causes of poor water heating include:

  • Malfunctioning controller heater relay
  • Worn or melted heating element
  • Blown heating circuit Hi-limit (fuse)
  • Broken or rodent-damaged wire to heating element

How Hot Do Dishwashers Get? Dishwashers typically reach about 160 degrees during the wash cycle and up to 170 degrees during the drying cycle. At these temperatures, plastic items near the heating element may melt, so it’s best to place plastic items on the top rack.

Can You Use a Dishwasher Without Hot Water? Yes, but it’s not ideal. Using cold water will still clean the dishes, but the cycle will take longer. Prolonged use of cold water may prematurely wear out the heating element.

Does a Dishwasher Use Less Hot Water Than Hand Washing? Yes. Hand washing with 120-degree water isn’t sufficient to kill food-poisoning pathogens.

How Long Do Dishwashers Run? A typical cycle lasts about 90 minutes, including drying. Preheating the water by running your kitchen sink for five minutes before starting the dishwasher can shorten the cycle, as less time is needed to heat the water.

Sanitizing cycles take longer because it requires more time for the water to reach the higher temperatures needed.

AWP Home Inspections offers home inspection services to homebuyers and sellers in West Central and Central Indiana. Contact us to request an appointment.